Fastening elements of the general type recited supra are disclosed in various embodiments in WO 2015/007277 A2 owned by applicant. They are used for fastening two components at each other wherein the invention is directed to the lamp industry, this means production and assembly of lamps for room and building illumination or for external illumination. In this field LED illuminants increasingly replace convention iridescent and gas discharge lamps. LEDs are typically arranged on circuit boards that are provided with conductive paths and connections for wiring. Furthermore the circuit boards of more complex illuminants also include control and regulation components. A unit of this type including a LED and a circuit board is also designated as LED unit or simply LED and is placed onto a lamp element which is typically not only used for support but also for heat dissipation.
The increasing popularity of LED illuminants requires automated fabrication methods for which the fastening devices currently used, e.g. bolts are less suitable.
The fastening devices known in the art use cut outs in the circuit boards and lamp components and recesses for bolt attachment in order to facilitate interlocking or spread rivet type fastening elements, in any case insertable fastening elements to facilitate the attachment of the LED illuminant at the lamp element.
A contact pressure between the LED circuit board and the heat dissipating lamp component is particularly significant. The contact pressure has to be defined within a particular band width in order to provide an optimum heat dissipation and thus an optimum service life of the LED. Therefore clamping the LED circuit board and the lamp component together is very important. In addition to correct contact pressure the clamping elements of the fastening elements also compensate fabrication tolerances.
At first glance there are certain commonalities between fastening devices for fastening LED illuminants and similar fastening devices for automotive applications. In fact the fastening devices for fixing LED illuminants require much smaller structures, thus the attachment devices of WO 2015/007277 A2 have a maximum length of 7 mmm and a maximum width of 5 mm and are thus much smaller than the non-related art in the automotive industry.
The fastening elements from the related art by applicant recited supra have proven very successful in practical applications. Still mounting LED illuminants and handling the associated fastening elements shall be further simplified.